Aircraft: A320
Phase of flight: Climb
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Weight And Balance; Flight Deck / Cabin / Aircraft Event Illness / Injury; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor

Within moments of turning on the PACKS after takeoff both crew noticed a strong smell I would characterize as musty/moldy/body odor. As I pondered my next move the First Officer asked if I smelled that; followed shortly by I think that is the dirty sock smell. Her next comment of 'I'm already feeling nauseated' broke my reverie and both crew members as well as our jump seat occupant donned O2 masks immediately. We attempted to perform the 'Elimination of odor in the flight deck/cabin' procedure. We were hindered in our efforts by the fact that the binder of the first QRH employed broke in half when the First Officer attempted to retrieve it leaving her with nearly 200 loose pages of former QRH. I provided my QRH but the procedure is missing from the back; or anywhere; in this particular aircraft's QRH. Volume 2 was referenced for the procedure which was challenging to find given the constraints of the mask.We leveled the aircraft at 16;000 feet and as the First Officer was already experiencing symptoms I elected to return the aircraft to [the departure airport] without further delay. ATC was notified of our intentions and I terminated the previously mentioned checklist that involved troubleshooting the air packs due to the difficulty in following a procedure through the mask on the Ipad and our need to prepare the aircraft for an air turn back. I never did feel I was able to get a real idea of which pack might be causing the odor. As we descended through 10;000 feet I turned off BOTH packs since I had been unable to determine the source of the odor and opened the ram air valve in an effort to provide as much fresh air to the cabin as possible. The First Officer ran the overweight landing checklist as we were approximately 3000 pounds above max landing weight. ATC vectored us for an ILS Approach which terminated in a successful landing. The aircraft was met by Fire and EMS as well as representatives from flight operations; inflight and local [authorities].The aircraft was deplaned without further incident. The odor event; crew usage of O2 and overweight landing were documented in the logbook post flight. The flight and cabin crew debriefed with the aforementioned parties prior to departing the scene. Both the Airbus and [company] odor/fume reporting sheets were completed and delivered to maintenance. Both pilots and I believe all flight attendants reported to company provided medical care for evaluation afterwards. On further communication with flight attendants it appears at least some of them showed elevated levels of carbon monoxide in the blood tests their doctors performed. Even though the doctor was familiar with these ongoing odor events in the industry and was provided with [union] and IATA guidance for examination no blood testing of the pilots was completed. Perhaps the company [and other parties involved] can work towards a common strategy for post incident comprehensive physical examination of crew members to ensure all bases are covered.Ensure that the Elimination of Odor in Flight Deck/Cabin checklist is added to EVERY QRH in the fleet ASAP. I believe our fleet manager has been working very hard to see this happen. Trying to use an Ipad to find critical checklists while wearing a mask is very difficult even without the presence of visibility restricting particulates in the air. Continue working on resolution to this seemingly complex issue as it appears to affect a large portion of the fleet including both Boeing and Airbus aircraft. After takeoff; as we turned on the packs; I smelled an odor. I said; 'it smells like device fluid.' Then; within seconds; it got very strong and smelled to me like oil. I turned to the Captain and said; 'I think this might be that dirty socks smell. Do you smell that?' I started feeling nauseated and told my Captain. We both immediately donned our oxygen masks. Our jumpseater did as well. I went to my QRH to verify the memory item was complete then to start the Elimination of odor in the flight deck checklist. The QRH binder busted open and I had pages everywhere. Then; I used Captain's to find out the procedure; which was not in this QRH. So; we went to Vol. 2 and decided to level off at 16;000 feet and return to [the departure airport].I advised ATC we had fumes in the aircraft and we needed to return to [the airport]. The Captain gave me control of the aircraft and continued the checklist. We could not determine which pack the fumes were coming from. We turned off both packs through 10;000 feet and opened the Ram Air Valve. I then gave control back to the Captain and contacted company and ran the overweight checklist. We were vectored to land and landed. The fire department and EMS met the aircraft. We successfully deplaned aircraft. All paperwork was filled out and logbook entries made. Maintenance was there and received the odor reporting sheets. The entire flight crew went to get medical treatment evaluations. I personally felt very dizzy and nauseated for the first hour and it lessened as I got fresh air. This fume issue seems to be occurring to often and needs to be resolved. I think Maintenance is having a hard time duplicating the issues we are experiencing. A320 flight crew reported odors in the cockpit requiring a return to the airport.